I haven't tested these; I don't even know how to import properly as FBX (never tried). Note, however, that the hi-res versions are not free.
http://www.cgchannel.com/2020/11/download-15-free-hi-res-tree-models-in-fbx-format/
Good find.
Terragen will not import FBX models (yet). You'll have to convert the files to obj in your favourite modelling package.
Ah, good to know. Thank you.
Thanks for sharing! No textures makes it a little hard to work with for some but still probably useful.
Blender does a straight forward import and export if you don't have something else better.